1. Field of the Invention
This invention relates to a key top, and more particularly, to a key top having a sign on the top portion.
2. Description of the Prior Art
At the top portion of a key top of electronic desk top calculators and typewriters there is usually provided a sign including letters or numerals which designates a type of signal input by driving the key or a type of mechanism for driving. The portion of the key top having the sign is pushed with a finger or the like so that the sign on a key top needs to be durable and of abrasion resistance. In order to satisfy such conditions there are widely used two-color shaped key tops produced by two-color shaping.
The two-color shaped key top is produced by shaping the outside of a key top and pouring a resin in a first mold capable of providing a vacant part in the key top where a sign is to be formed (first step) and fitting the key top thus obtained in a second mold and pouring another resin having a color different from that of the above mentioned resin to fill the vacant part with the other resin (second step).
The sign at the top portion of the key top thus produced is very strong and has an abrasion resistance corresponding to the resin forming the sign.
As mentioned above, the key top having a sign formed by a two-color shaping process is excellent because it has various characteristics necessary for a key top. However, when only a small amount of key tops are produced by one mold corresponding to each sign, the unit cost of the key top is very high. In addition, the sign is formed as a vacant part in the first step so that it is difficult to manufacture a mold for a complicated sign such as chinese characters and the like.